Microfluidic devices are used in a wide range of applications. Typically, a microfluidic device is defined to handle small fluid volumes (μL, nL, pL etc.), have a small size with at least one dimension in the micrometer range, and/or use effects of the micro domain. In such devices fluids may be moved, mixed, separated or otherwise processed. Numerous applications employ passive fluid control techniques like capillary forces.
One important area of us of microfluidics is in medical devices. Microfluidic devices may be used in analytical or therapeutical applications, e.g. to administer medications or to handle samples of bodily fluids.
In many applications it may be important to be able to define volumes of liquids to be handled and processed by the microfluidic device. However, today there is still a problem to find a simple and efficient solution to defining a liquid volume in such a device.